#include <stdio.h>

int main(){
	int result;
	char grade;
	printf("请输入你的成绩：\n");
	scanf("%d",&result);
	if(result < 60){
		grade = 'D';
	}
	else if(result <= 80){
		grade = 'C';
	}
	else if(result <= 90){
		grade = 'B';
	}
	else if(result <= 100){
		grade = 'A';
	}
	else {
		grade = ' ';
	}
	printf("你的成绩是%c\n",grade);
}
